Development of a self-cleaning rotating drum Artemia nauplii concentrator

A concentrator is an essential part of the Artemia production system for the concentration, rinsing, and harvesting of the nauplii in commercial hatcheries. Traditional concentration devices such as the plankton screen bags and the welded wedge screen concentrator all have the clogging problem that limits the concentration flow rate and increases the risk of damage of the nauplii. A novel self-cleaning rotating drum Artemia nauplii concentrator has been developed. The rotation of the drum creates a continuous water flow across the filtering screen to wash the nauplii off the screen thus creating an efficient self-cleaning effect that is also safe to the nauplii. The concentrator was tested at three rotation speeds to compare the filtration and survival rates for nauplii densities from 500 to 8000 nauplii ml−1. The rotation of the drum maintained the filtration rate to within 90% of the initial rate at 8000 nauplii ml−1, as compared to only 10% when there was no rotation. At a rotation speed of 40 rpm, the concentrator could process 200 l of nauplii liquid from an initial concentration of 200 nauplii ml−1 to a final concentration of 13,500 nauplii ml−1 in less than 9 min and with a survival rate of more than 99%. The filtration rate per unit screen area of the rotating drum concentrator was more than twice that of the welded wedge screen concentrator and about eight times that of the plankton screen bag. Compared with the other two devices, the rotating drum concentrator has the advantages of a faster and more stable filtration rate, higher final nauplii concentration, non-detectable leakages, and fully automatic operations that could be programmed to suit varying hatchery requirements. The rotating drum concentrator could save time and labor, ensure the safety of the nauplii, and provide the flexibility of unmanned operations and precision control for the automatic production of the Artemia nauplii in the hatcheries.